You have an Atlas and can't get a single shaft to work? I guess I don't understand because I have an Atlas and a single u-joint shaft up front with no issues. Are you binding up the yokes when the suspension is cycled?
The single u-joint shaft up front is working on the atlas as far as u joints and such go. I did build my own with a kit so it is long travel so I wouldn't have the issue about pulling it apart again. So the issue isn't with the front shaft other than I did not get it as straight as I thought i did and i am getting some vibration from it if I try to run in 4 hi.
So the issue I was having will take a little back story to make sense. I was originally running a double cardigan shaft for the rear of the scrambler that I had made by a shop local. Shaft works great and other than I would like it to have thicker walled tube. The issue I had was I was short on time when I got it made and the shop thaught they knew what I needed better than I did. The flange they put on the shaft was not compatable with the flange in my atlas so I re drilled my flange to make it all work so I wanted to change this when I got a chance. At nationals I tore up a front driveshaft and didn't have a spare so I decided if I was going to build a front shaft i should build a rear as well.
I also tore up my 14 bolt at nationals and put everything into a new housing. While I was doing this I wanted to set up the rear so I could use a standard 2 joint driveshaft. I figured this would let me build 3 shafts, a front, a rear and a long travel that should work for both as a spare. So I set up my pinion angle at 3 degrees to match my output of the transfer case. New spring pads and u bolts everything set for standard 2 u joint shaft. Built rear shaft and both ends bound up so I tried to clearance yokes. NOPE too much angle. So I called the shop I got the parts from to see if there was another solution. They suggested that I point the pinion at the output as you would for a double cardigan shaft and still run just 2 u joints. The shop along with a bunch of folks I have wheeled with are running in this set up and seem to be fine for an off road only rig.
Well it did not work for me at all, I think the angle is just too much at the transfer case as just a slight increace in RPM the driveshaft would rattle like a bearing coming apart. Best I can figure is that my angles are too steep being I am still stock wheelbase to utilise this trail set up.
So currently I am running my double cardigan shaft in the rear and one I built to be long travel in the front. I can go down the road at 60 (about all she has on the little tires) in 2 wheel drive just fine and am good in 4 wheel to about 30 or so. I think I am going to give it a run next week at the Annual Trail ride her in Virginia and see how it all does. I might cut the front back apart and try one more time to get it straight after the event. As for being able to run a 2 u joint shaft in the rear I don't think I will ba able to unless I take some height out and stretch the rear to make the driveshaft longer and the angles less steep.
Hope that makes more sense as it has been quite a bit of ups and downs the last couple weeks trying to get ready for the upcoming ride. While I would like to say it is good to go now its not and I will be trying to figure out what the next iteration of the scramblers growth will be. I am pretty frustrated trying to get it all to work the way I want right now and have been pretty close to cutting everything off the frame and starting from scratch.